My problem occurs almost every time (but not all the time) when my screen saver has been active for a while. The other occurance is when I initiate a shut down of my system form the KDE log out menu (about 30-40% of the times when I shut down my system).

The symptom is that the screen freeze and the keyboard and mouse does not respond. The system appears totally frozen and I have to do a forced shut down with the power button. This circumstance makes it really hard (or impossible) to detect anything in log files (dmesg, /var/log/messages, xsession errors or any other log file).

You may also want to try the nvidia drivers. It's odd but sometimes one rig works great with the 3rd party nvidia drivers but another rig works best with the Nvidia drivers. So, if one could be causing a problem, try the other.

That is not to say that the video drivers is causing the problems but it could be. I had a problem with mine freezing a good while back on a older rig. Turned out that downgrading the nvidia drivers fixed it. For some reason, my card did not like that version. The computer was actually seeing the keyboard keystrokes and the mouse moving but the video card was not showing it on the screen. I figured this out by going to a console, logging in and typing in the reboot command blindly. A few seconds after typing in the reboot command, the system rebooted and the BIOS screen was there. Weird.

I also agree that you should try a newer kernel. Each release has fixes and you may need one of those fixes. While at it, double check the section for input devices and make sure you have the right ones. Could be that something has changed and you didn't realize it.

You may also want to try the nvidia drivers. It's odd but sometimes one rig works great with the 3rd party nvidia drivers but another rig works best with the Nvidia drivers. So, if one could be causing a problem, try the other.

Do you mean I have to set

Code:

VIDEO_CARDS="nvidia"

instead of

Code:

VIDEO_CARDS="nouveau"

in /etc/make.conf

and remerge nvidia-drivers?

And yes I agree I have an old kernel :) I use to enjoy the stability of my system and I upgrade the kernel quite seldom. But some thime I guess it becomes inevitable to up grade._________________/Phil

This could be a problem. In one section you tell it to use nvidia then in the other section you tell it to use vga. Unless you have two cards, I don't think that will work. You need to remove one or the other and keep the one you have installed. If you do have two cards, I think you have to have a section that tells which card goes with what. I have never had two cards so not sure how that would work but read about it a couple times.

I don't see anything else but that doesn't mean someone else won't come along and see something else.

Unfortunately my hopes were shattered last night when my system experienced a total freeze again. The meassures above did not solve my problem.
The fact that the feezes occur at two distinct runtime states:

1. When the screen-saver has been active, somewhere beetween 20 minutes to several hours (the freeze occurs at any point in time between those extremes)

2. When I issue the system shut down command or a log out command from the KDE launch menu

should lead to some clues of what actually casuses the freezes. But my knowlegde of how the SW is build and interact is to limited to figure out what._________________/Phil

Last edited by philip on Fri Sep 14, 2012 1:59 pm; edited 1 time in total

VideoRam mem
This optional entry specifies the amount of video ram that is
installed on the graphics board. This is measured in kBytes.
In most cases this is not required because the Xorg server
probes the graphics board to determine this quantity. The
driver-specific documentation should indicate when it might
be needed.

I have also ruled out any misconfiguration in the user specific settings. I created a test_user, logged in as test_user and let the screen saver be active for a while. The freeze came after approx an hour._________________/Phil

I suspect my problem may be hw related. The reason for my suspision is that the freezes occur fairly random in time. Eventhough they almost always occur when the screen saver has been acitve for a while and thus seem to be consistent with a certain sw execution sequence, I recently have had a couple of freezes while just working away on the machine.

Today I installed a new graphics card; ZOTAC GeForce GT 640 2GB PhysX CUDA. I will soon find out if my problem persist or if it actually was a hardware problem._________________/Phil

Last edited by philip on Fri Sep 21, 2012 4:41 pm; edited 1 time in total

I confirm that my problem was due to an ageing graphics card and thus HW related. With my new graphics card I have not had a freeze for 24 hours, while the screen saver has been active all the time.

The ageing can probably have to causes; The first may be the HW components themselves and the second may be old versions of GPU SW support, like Open GL, not compatible with recent graphics drivers._________________/Phil